1. Field of the Invention
The present invention relates to an image pickup apparatus including a lens barrel.
2. Description of the Related Art
A conventional image pickup apparatus includes a zoom mechanism configured to move a plurality of optical lenses in an optical axis direction so as to change imaging magnification. Japanese Patent Laid-open No. 2008-33153 discloses a lens barrel configured to move a plurality of lens holders holding a plurality of lenses in the optical axis direction by a cam ring and to regulate movement of the lens holders in a rotational direction by a rotation regulator. Such a configuration allows the optical lenses to be moved to desired positions. The lens barrel disclosed in Japanese Patent Laid-open No. 2008-33153 is configured to allow part of a straight barrel to be inserted into space left by retracted barriers, penetrating from a back of the lens barrel to a front thereof. Japanese Patent Laid-open No. 2011-154167 discloses a lens barrel configured to allow lenses to be inserted into an opening formed by barriers at image capturing.
In recent years, a lens barrel has been required to be small and to have as long its length in an extended state as possible.
In such a configuration disclosed in Japanese Patent Laid-open No. 2008-33153, the penetration of the straight barrel to the front of the lens barrel contributes increasing a straight move amount of units inside thereof. However, the configuration cannot have long cam grooves, which limits its cam stroke. In the configuration disclosed in Japanese Patent Laid-open No. 2011-154167, a barrier unit and a first lens unit are separated in two. This separation increases a thickness of the configuration in an optical axis direction and thus decreases a length of a cam barrel accordingly, which results in a shorter cam stroke.
Recent developments have further downsized image pickup apparatuses (cameras), and small image pickup apparatuses are most needed in the market. It is thus needed to configure a lens barrel having high optical magnification while avoiding increasing the size of an image pickup apparatus, which is achieved by providing a long cam stroke.